All modem sailboat rigs position the mast directly ahead of luff of the sail. In this fashion the mast interferes with the airflow at the vital leading edge of the sail. Lateen rigs are an attempt to separate the supporting mast from the mainsail. Today this rig is found in the popular Sunfish. This rig, however, suffers an inherent deficiency since on one tack the sail presses against the mast. This distorts the aerodynamic shape of the sail and penalizes performance.
In the prior art there are attempts freeing up the luff of the sail as in the Laurent U.S. Pat. No. 3,173,395 but his vessel can not tack as the boom remains on one side of the mast. Another illustration of a free luff is seen in U.S. Pat. No. 1,856,803 in which the boom is slidably coupled to a traveler to space it from the mast. There are also examples of rigs with free luffs as in PCT publication WO 91/18788 dated 12 Dec. 1991 that is aimed at a rig with “lifting” benefits for multihulls by angling the sail away from the vertical that creates a lift component.
The instant invention has no lateen spar or slidable or rotating boom as the boom and sail are to leeward of the mast on one tack and to windward of the mast on the other tack. In other words the boom and sail are always on one side of the mast.